1. Field of the Invention
The present invention relates to a display control apparatus, more particularly to a method and apparatus for controlling a plurality of memory planes in a writing operation in a display control apparatus of a graphic system of a personal computer. With the present invention, it is possible to simultaneously write different data on a data bus into a plurality of memory planes, for example, three memory planes storing tricolor data, i.e., red (R), green (G), and blue (B) data. With such a system, a color image displayed on a color cathode ray tube (CRT) can be quickly changed to another desired color.
2. Description of the Prior Art
Popularization of personal computers in various different fields has recently led to use of various graphic systems as input/output devices. In many cases, a color CRT is used as the graphic system. As is well known by persons skilled in the art, a color image on a CRT consists of by R, G, and B dots. The color image is changed by reading from and writing into memory planes storing tricolor data. When changing the color, i.e., when changing a displayed color image to another color, the selection of the memory planes and the change of logic in the selected memory planes must be sequentially performed. As a result, it is not possible to increase the speed of processing (change) of the color image displayed on the CRT.